In recent years, consumers have been using a greater number of portable devices using rechargeable batteries. While such units are convenient, these batteries must be periodically recharged. Generally, a portable device containing a rechargeable battery includes a charge controller that is coupled to the battery and to an input for receiving power from an external source. The charge controller, based on signals from the battery, typically controls the flow of current to the battery. To accommodate this scheme, multiple contacts between the battery and the charge controller are generally present. For example, one of the contacts may be an input, while another may be a ground connection. Other contacts may be available for transferring information, such as voltage conditions and operational data, from the battery to the charge controller.
As portable devices have become more complex, the number of required contacts has increased. However, such increases in the number of contacts have led to increases in the expense of manufacturing these systems and the likelihood of malfunctions.